<!DOCTYPE html>  
<html>  
 <head>  
 <meta charset="utf-8">  
 <title></title>    
 <script type="text/javascript">  
  function count(){  
        var a = parseInt(document.getElementById("tex1").value);  
        var b = parseInt(document.getElementById("tex2").value);  
        var selectSign = document.getElementById("select").value;  
  
        switch (selectSign)  
        {  
        case '+': answer = a+b;break;  
        case '-': answer = a-b;break;  
        case '*': answer = a*b;break;  
        case '/': answer = a/b;       
        }  
        document.getElementById("fruit").value = answer;  
  }  
 </script>   
 </head>  
<body>  
  <input type="text" id="tex1" />  
  <select id="select">  
        <option value="+">+</option>  
        <option value="-">-</option>  
        <option value="*">*</option>  
        <option value="/">/</option>  
  </select>  
  <input type="text" id="tex2" />  
  <input type="button" value=" = " onclick="count()" />  
  <input type="text" id="fruit" onclick="count()" />  
</body>  
</html>  
